My cycle avg is 26, last was 19, hv low tsh, period on 16th up sex 21st, cramps 28th, gas 31st, please tell me im not pregnant. could it be ovulation?

Too soon to tell: Conception, as defined by the generation of a fertilized ovum, occurs within day or so of the sex. However, it takes about two weeks for the embryo to make enough HCG to produce a positive pregnancy test. Blood test may be done a day after a missed period. Home pregnancy tests should be done 4-5 days after the missed period. Use first morning urine and follow instructions for the test carefully.